One box cars and the like are designed not only to accommodate occupants but also to load cargo, so that an average number of seats and a cargo space are provided. Additionally, in many cases, seats other than a driver's seat and a front passenger's seat are made up of detachable seats or movable seats. Then, when there is much cargo to be loaded in the vehicle, the detachable seat or seats are detached or the movable seat or seats are moved to ensure a loading space for the cargo.
A lock apparatus used to fix the detachable seat or the movable seat is mounted on either of a vehicle main body or the seat and fixes the seat or the like by being brought into engagement with a striker which is mounted on the other of the vehicle main body and the seat. In this way, the lock apparatus used to fix the detachable seat or the movable seat is mounted on either of the vehicle main body and the seat and includes a hook lever which is brought into engagement with the striker which is mounted on the other of the vehicle main body and the seat. The hook lever is intended to be brought into engagement with the striker which enters the lock apparatus relative thereto to hold it. There are hook levers, one of which moves from an engagement position (a waiting position) to an opening position as a result of the striker entering the lock apparatus and thereafter moves from the opening position to the engagement position to thereby be brought into engagement with the striker that has entered the lock apparatus to hold it, and the other of which moves from an opening position to an engagement position after the striker has entered the lock apparatus to thereby be brought into engagement with the striker to hold it.
The hook lever which moves from the engagement position (the waiting position) to the opening position as a result of the striker entering the lock apparatus and thereafter moves from the opening position to the engagement position to thereby be brought into engagement with the striker to hold it needs to be provided with a sliding contact surface (a sliding contact surface which is inclined with respect to the entering direction of the striker) which is brought into sliding contact with the striker which enters the lock apparatus relative thereto to thereby move the hook lever from the engagement position (the waiting position) to the opening position, and therefore, the hook lever inevitably becomes large in size, and the lock apparatus becomes large in size in the moving direction of the hook lever (for example, refer to PTL 1).
On the other hand, the hook lever which moves from the opening position to the engagement position after the striker has entered the lock apparatus to thereby be brought into engagement with the striker to hold it cannot move from the opening position to the engagement position by itself, and therefore, the hook lever needs a guide lever which moves the hook lever from the opening position to the engagement position (for example, refer to PTL 2).
For example, in the case of PTL 2, a lock apparatus is proposed which includes, in addition to a hook lever, a guide lever which moves the hook lever from an opening position to an engagement position by rotating as a result of an end portion thereof moving from an entrance side towards a deep side in an entering direction of a striker. The guide lever described in PTL 2 is designed to rotate about a guide shaft provided at the entrance side in the entering direction of the striker. Thus, in order for the end portion to move from the entrance side to the deep side in the entering direction of the striker, a long length needs to be taken from an end portion of the guide shaft (a rotation center of the guide lever) to the end portion, and this enlarges the lock apparatus in the moving direction of the guide lever. The guide lever moves in the same direction as a direction in which the hook lever moves, as a result of which the lock apparatus is enlarged in the moving direction of the hook lever.
In addition, as a fixing construction of a detachable seat or a movable seat which employs the lock apparatus, for example, a hinge hole is provided at an end of a rail which supports the seat, while the hook lever is mounted at the other end of the rail. Then, one end portion of the rail is mounted so that the hinge hole supports rotatably a hinge shaft provided on a floor surface, whereby the detachable seat or the movable seat is allowed to rotationally move about the hinge shaft. In addition, the hook lever mounted at the other end of the rail is brought into engagement with a striker provided on the floor surface in such a state that the detachable seat or the movable seat is allowed to rotationally move about the hinge shaft, whereby the detachable seat or the movable seat is fixed to the floor surface.
Here, when the distance between the hinge shaft and the striker is shorter or longer than a reference distance due to a mounting error of the hinge shaft or the striker or the like, the hook lever is not allowed to engage with the striker, and therefore, the detachable seat or the movable seat cannot be fixed to the floor surface.
To eliminate these situations, a lock apparatus is proposed in which a case is extended to an area above a rotational area of a hook lever to configure a mounting portion, and a round hole (a mounting hole) is provided in the center of the mounting portion, while arc-shaped elongated holes (mounting holes) which are centered at the round hole are provided on both sides of the round hole. According to this lock apparatus, even when the distance between a hinge shaft and a striker is shorter or longer due to a mounting error of the hinge shaft or the striker, the hook lever is allowed to engage with the striker by the lock apparatus rotationally moving around the round hole, whereby the detachable seat or the movable seat can be fixed to the floor surface (for example, refer to PTL 3). However, since the case is extended to the area above the rotational area of the hook lever to configure the mounting portion, the lock apparatus is enlarged as a whole. Additionally, since the round hole and the elongated holes are provided in positions spaced away from the striker which is in an engagement state, in the event that a large force is applied to the hook lever via the striker, there is a possibility that the case is turned up.